title: Purification of NADPH-linked and NADH-linked quinone reductases from liver cytosol of sea bream, Pagrus major.
abstract: Quinone reductases in sea bream, Pagrus major, were investigated using menadione as a model quinone. Both NADPH-linked and NADH-linked quinone reductase activities were detected, in varying degrees, in all tissues examined. In the liver, these activities resided in its microsomal and cytosolic fractions. The cytosolic activity was markedly inhibited by cupric sulfate and p-chloromercuribenzoate. However, little effect was observed with dicoumarol, a potent inhibitor of DT-diaphorase. The NADH-linked activity was more resistant to heat inactivation than the NADPH-linked activity. The NADPH-linked quinone reductase was purified from the liver cytosol by chromatography with DEAE-cellulose, hydroxyapatite and AF-Blue Toyopearl. The molecular weight of the enzyme was estimated to be 68,000 by gel filtration and 32,000 by SDS-PAGE. The NADH-linked quinone reductase was purified from the liver cytosol by heat treatment, fractionation with ammonium sulfate and chromatography with phenyl-Toyopearl, hydroxyapatite, DEAE-cellulose and hydroxyapatite. The molecular weight of the enzyme was estimated to be 124,000 by SDS-PAGE and 126,000 by gel filtration.
authors.affiliation: Institute of Pharmaceutical Science, Hiroshima University School of Medicine, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kitamura
authors.forename: K
authors.initials: K
authors.lastname: Tatsumi
mesh_terms: D000818:Animals; D003600:Cytosol / Q000737:chemistry / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D005399:Fishes; D006358:Hot Temperature; D007564:Japan; D008099:Liver / Q000166:cytology / Q000201:enzymology*; D009243:NAD / Q000378:metabolism*; D009249:NADP / Q000378:metabolism*; D010473:Perciformes; D011808:Quinone Reductases / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism*; D014018:Tissue Distribution; D014812:Vitamin K / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D009243:NAD; D014812:Vitamin K; D009249:NADP; D011808:Quinone Reductases